The invention concerns a method for starting a motor vehicle on an inclined route. In particular, the invention concerns driver-independent support for starting a motor vehicle on an inclined route.
Systems which support the processes of stopping and starting a motor vehicle on a downhill or uphill gradient are known. Some of these systems generate a brake force, independently of the driver, by means of a brake system of the motor vehicle, when the motor vehicle comes to a standstill on an inclined route, or maintain a brake force generated by the brake system, independently of the driver, after the motor vehicle reaches a standstill. Whether the motor vehicle reaches the standstill because of brake actuation by the driver, brake actuation independently of the driver or the motor vehicle coasting is insignificant here.
Such a system is known, for instance, by the name “Hill Assist”. This system is constructed so that if, after the standstill is reached, the driver does not actuate the brake system, it maintains the brake force for a specified holding time (typically about 0.6-2 seconds), to make it easier for the driver to start on the inclined route. After the predetermined holding time expires, if no successful starting occurs, the brake force of the motor vehicle is continuously or abruptly withdrawn. Consequently, the motor vehicle begins to roll downhill in an uncontrolled manner, at a more or less quickly increasing speed.
The introduction of such an uncontrolled driving state may not, or not until later, be noticed by the driver of the motor vehicle, so that the motor vehicle can cause damage during its uncontrolled downhill movement. In particular, abrupt release of the brake actuation, independently of the driver, can result in the driver being taken by surprise by the changed driving situation and losing control of the motor vehicle. Accordingly, it would be desirable to avoid an uncontrolled driving state of a motor vehicle when a driver-independent hill holding function ends.